My cat score is 77.47 %le Is it enough ???

Hi, the percentile score is not enough for you to get admission into IIM. You need to improve the score. But still you can check the college websites for their cut-off. It will provide you with the rough estimate of how much percentile is required for converting admission call.

CAT score cut-offs vary for different castes. Without that information, it is difficult to say.

Sorry! Your chances are very slim. IIM Shillong although favours good background as well but this percentile in general category is well beyond this year's admission criteria.